Environmental permittivity-asymmetric BIC metasurfaces with electrical reconfigurability

Area of Science:

• Nanophotonics
• Metasurfaces
• Optical Engineering

Background:

• Precise nanoscale light manipulation is crucial for advanced optical devices.
• Photonic bound states in the continuum (BICs) offer light control but are limited by fixed geometry and fabrication sensitivity.
• Existing methods for quasi-BIC (quasi-bound states in the continuum) require geometric asymmetry, hindering reconfigurability.

Purpose of the Study:

• To introduce and demonstrate a novel concept of environmental symmetry breaking for tunable quasi-BIC resonances (ε-qBICs).
• To overcome the limitations of geometric symmetry breaking in traditional BICs.
• To achieve electrically reconfigurable nanophotonic devices through external environmental modulation.

Main Methods:

• Developed ε-qBICs by embedding identical resonators in a dielectric environment with spatially varied refractive indexes.
• Integrated polyaniline (PANI), an electro-optically active polymer, to enable electrical tuning of the dielectric environment.
• Utilized environmental symmetry breaking to activate quasi-BIC resonances without altering resonator geometry.

Main Results:

• Demonstrated electrically reconfigurable ε-qBICs using PANI integration.
• Achieved rapid switching speeds and exceptional durability in the reconfigurable system.
• Showcased enhanced optical response to environmental perturbations through permittivity modulation.

Conclusions:

• Environmental symmetry breaking offers a new degree of freedom for light manipulation via permittivity modulation.
• This approach overcomes limitations of geometric BICs, enabling reconfigurable metasurfaces.
• The developed ε-qBICs strategy paves the way for advanced on-chip optical devices and sensing applications.